Vortex Viper®6.5-20x50 PA Owner's Manual

Vortex Viper®6.5-20x50 PA Owner's Manual
RETICLE
V ORTEX ® M IL D OT R ETICLE
This is an extremely versatile reticle that allows high-precision
shooting as well as distance estimation and compensation for long
range bullet drop and wind drift.
It is very important to understand that your riflescope must be set to
a magnification of 14x in order to use the listed subtensions correctly.
The standard center crosshair can be used at any magnification.
Vortex Mil Dot Reticle
Subtensions
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RETICLE
The Mil Dot and MRAD Measurements
Ranging
The Vortex Mil Dot reticle features subtensions that are based on the
radian. The terms mil and mrad refer to a milliradian—a distance that
equals 1/1000 of a radian.
In order for you to range using the reticle, you must know either the height
or width of some portion of the target or a nearby object.
A radian is the angle subtended
at the center of a circle by an
arc that is equal in length to
the radius of the circle. There
are 6.283 radians in all circles
and 1,000 milliradians in each
radian. This calculates to a total
of 6,283 milliradians in a circle.
The mil dot reticle uses this
angle and arc scale to estimate
range and bullet trajectory drop.
1 Mil Width at Various Distances
100 yards
3.6 inches
100 meters
10 cm
200 yards
7.2 inches
200 meters
20 cm
300 yards
10.8 inches
300 meters
30 cm
400 yards
14.4 inches
400 meters
40 cm
500 yards
18.0 inches
500 meters
50 cm
600 yards
21.6 inches
600 meters
60 cm
700 yards
25.2 inches
700 meters
70 cm
800 yards
28.8 inches
800 meters
80 cm
900 yards
32.4 inches
900 meters
90 cm
1,000 yards
1 yard
1,000 meters
1 meter
Known Dimension Examples
• A whitetail buck’s brisket-to-back distance of 18 inches
• A standing ground hog height of 10 inches
• A target measuring 20 inches in diameter
Using your reticle, see how many mil (mrad) spaces span the portion of a
known dimension and use this information in a simple formula to calculate
the distance to your target.
Target’s Known Width or Height in Yards x 1000
Target’s Width or Height in Mils or MRADs as Measured on Reticle
Target’s Known Width or Height in Meters x 1000
Target’s Width or Height in Mils or MRADs as Measured on Reticle
Target’s Known Width or Height in Inches x 27.8
Target’s Width or Height in Mils or MRADs as Measured on Reticle
A mil (mrad) will always
subtend one unit of drop
for each 1,000 units of
distance.
= Range in Yards
= Range in Meters
= Range in Yards
Example
Let’s say your target is a coyote and you know that a nearby fence post
measures 36 inches in height. With
your riflescope set at the correct
magnification, place the reticle on
the fence post with the horizontal
crosshair even with the ground. You
see that the fence post spans 2 mils
(mrads). Convert the 36-inch fence
post height into yards and use the
formula to calculate the distance to
your target. In this case, your coyote is
at a distance of 500 yards.
1 Yard (36”) x 1000
= 500 Yards to Coyote
Example
1 mil (mrad) will subtend
1 yard at 1,000 yards or
1 meter at 1,000 meters.
2 Mils (MRADs)
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RETICLE
Windage Compensation
Holdover
The mil dot reticle can be used to compensate for bullet wind drift.
You should have the mrad-based ballistic data available for your
particular firearm and ammunition at all distances. As in ranging,
you’ll need to have your riflescope set at the correct magnification in
order to accurately hold for wind.
Once you have ranged a target, the mil dot reticle can be used to
quickly estimate proper holdover on longer shots. You should have
the mrad-based ballistic data available for your particular firearm
and ammunition at all distances. As with ranging and windage
compensation, you will need to have your riflescope set at the correct
magnification.
Example
You’ll be shooting at a target that is 400 yards away in what you
estimate to be a 10 mph crosswind. Your ballistic data tells you that
the bullet will drift .5 mrads in this crosswind. In order to correctly
compensate for the crosswind and make your shot, you’ll need to hold
1/2 mil into the wind.
Example
Let’s say you’ve ranged a deer and determined that it is 300 yards away.
Your rifle is zeroed in at 100 yards and your ballistic data tells you that
your bullet will drop 1 mrad at 300 yards. Therefore, you’ll need to hold
the center crosshair 1 mil (mrad) higher than the deer’s vital zone in
order to make your shot.
In this example of shooting
at 400 yards in a 10 mph
crosswind blowing from the left
to the right, you would put the
center of the crosshair 1/2 mil
(mrad) to the left of your target.
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At 300 yards, put the center
of the crosshair 1 mil (mrad)
higher than the deer’s vitals.
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